kernel/linux.git/fs/fuse/inode.c, branch v5.15.208

fuse: fix UAF in rcu pathwalks

2024-09-04T11:23:23+00:00

[ Upstream commit 053fc4f755ad43cf35210677bcba798ccdc48d0c ] ->permission(), ->get_link() and ->inode_get_acl() might dereference ->s_fs_info (and, in case of ->permission(), ->s_fs_info->fc->user_ns as well) when called from rcu pathwalk. Freeing ->s_fs_info->fc is rcu-delayed; we need to make freeing ->s_fs_info and dropping ->user_ns rcu-delayed too. Signed-off-by: Al Viro Signed-off-by: Sasha Levin

fuse: verify {g,u}id mount options correctly

2024-08-19T03:45:11+00:00

commit 525bd65aa759ec320af1dc06e114ed69733e9e23 upstream. As was done in 0200679fc795 ("tmpfs: verify {g,u}id mount options correctly") we need to validate that the requested uid and/or gid is representable in the filesystem's idmapping. Cribbing from the above commit log, The contract for {g,u}id mount options and {g,u}id values in general set from userspace has always been that they are translated according to the caller's idmapping. In so far, fuse has been doing the correct thing. But since fuse is mountable in unprivileged contexts it is also necessary to verify that the resulting {k,g}uid is representable in the namespace of the superblock. Fixes: c30da2e981a7 ("fuse: convert to use the new mount API") Cc: stable@vger.kernel.org # 5.4+ Signed-off-by: Eric Sandeen Link: https://lore.kernel.org/r/8f07d45d-c806-484d-a2e3-7a2199df1cd2@redhat.com Reviewed-by: Christian Brauner Reviewed-by: Josef Bacik Signed-off-by: Christian Brauner Signed-off-by: Greg Kroah-Hartman

fuse: don't unhash root

2024-04-10T14:18:38+00:00

[ Upstream commit b1fe686a765e6c0d71811d825b5a1585a202b777 ] The root inode is assumed to be always hashed. Do not unhash the root inode even if it is marked BAD. Fixes: 5d069dbe8aaf ("fuse: fix bad inode") Cc: # v5.11 Signed-off-by: Miklos Szeredi Signed-off-by: Sasha Levin

fuse: share lookup state between submount and its parent

2024-01-05T14:13:36+00:00

commit c4d361f66ac91db8fc65061a9671682f61f4ca9d upstream. Fuse submounts do not perform a lookup for the nodeid that they inherit from their parent. Instead, the code decrements the nlookup on the submount's fuse_inode when it is instantiated, and no forget is performed when a submount root is evicted. Trouble arises when the submount's parent is evicted despite the submount itself being in use. In this author's case, the submount was in a container and deatched from the initial mount namespace via a MNT_DEATCH operation. When memory pressure triggered the shrinker, the inode from the parent was evicted, which triggered enough forgets to render the submount's nodeid invalid. Since submounts should still function, even if their parent goes away, solve this problem by sharing refcounted state between the parent and its submount. When all of the references on this shared state reach zero, it's safe to forget the final lookup of the fuse nodeid. Signed-off-by: Krister Johansen Cc: stable@vger.kernel.org Fixes: 1866d779d5d2 ("fuse: Allow fuse_fill_super_common() for submounts") Signed-off-by: Miklos Szeredi Signed-off-by: Krister Johansen Signed-off-by: Greg Kroah-Hartman

fuse: limit nsec

2022-08-17T12:22:56+00:00

commit 47912eaa061a6a81e4aa790591a1874c650733c0 upstream. Limit nanoseconds to 0..999999999. Fixes: d8a5ba45457e ("[PATCH] FUSE - core") Cc: Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

fuse: make sure reclaim doesn't write the inode

2021-12-17T09:30:16+00:00

commit 5c791fe1e2a4f401f819065ea4fc0450849f1818 upstream. In writeback cache mode mtime/ctime updates are cached, and flushed to the server using the ->write_inode() callback. Closing the file will result in a dirty inode being immediately written, but in other cases the inode can remain dirty after all references are dropped. This result in the inode being written back from reclaim, which can deadlock on a regular allocation while the request is being served. The usual mechanisms (GFP_NOFS/PF_MEMALLOC*) don't work for FUSE, because serving a request involves unrelated userspace process(es). Instead do the same as for dirty pages: make sure the inode is written before the last reference is gone. - fallocate(2)/copy_file_range(2): these call file_update_time() or file_modified(), so flush the inode before returning from the call - unlink(2), link(2) and rename(2): these call fuse_update_ctime(), so flush the ctime directly from this helper Reported-by: chenguanyou Signed-off-by: Miklos Szeredi Cc: Ed Tsai Signed-off-by: Greg Kroah-Hartman

fuse: clean up error exits in fuse_fill_super()

2021-10-21T08:01:39+00:00

Instead of "goto err", return error directly, since there's no error cleanup to do now. Signed-off-by: Miklos Szeredi

fuse: always initialize sb->s_fs_info

2021-10-21T08:01:39+00:00

Syzkaller reports a null pointer dereference in fuse_test_super() that is caused by sb->s_fs_info being NULL. This is due to the fact that fuse_fill_super() is initializing s_fs_info, which is too late, it's already on the fs_supers list. The initialization needs to be done in sget_fc() with the sb_lock held. Move allocation of fuse_mount and fuse_conn from fuse_fill_super() into fuse_get_tree(). After this ->kill_sb() will always be called with non-NULL ->s_fs_info, hence fuse_mount_destroy() can drop the test for non-NULL "fm". Reported-by: syzbot+74a15f02ccb51f398601@syzkaller.appspotmail.com Fixes: 5d5b74aa9c76 ("fuse: allow sharing existing sb") Signed-off-by: Miklos Szeredi

fuse: clean up fuse_mount destruction

2021-10-21T08:01:39+00:00

1. call fuse_mount_destroy() for open coded variants 2. before deactivate_locked_super() don't need fuse_mount destruction since that will now be done (if ->s_fs_info is not cleared) 3. rearrange fuse_mount setup in fuse_get_tree_submount() so that the regular pattern can be used Signed-off-by: Miklos Szeredi

fuse: get rid of fuse_put_super()

2021-10-21T08:01:38+00:00

The ->put_super callback is called from generic_shutdown_super() in case of a fully initialized sb. This is called from kill_***_super(), which is called from ->kill_sb instances. Fuse uses ->put_super to destroy the fs specific fuse_mount and drop the reference to the fuse_conn, while it does the same on each error case during sb setup. This patch moves the destruction from fuse_put_super() to fuse_mount_destroy(), called at the end of all ->kill_sb instances. A follup patch will clean up the error paths. Signed-off-by: Miklos Szeredi